inhibition

/in'i bish"euhn, in'hi-/, n.

1. the act of inhibiting.

2. the state of being inhibited.

3. something that inhibits; constraint.

4. Psychol.

a. the blocking or holding back of one psychological process by another.

b. inappropriate conscious or unconscious restraint or suppression of behavior, as sexual behavior, often due to guilt or fear produced by past punishment, or sometimes considered a dispositional trait.

5. Physiol.

a. a restraining, arresting, or checking of the action of an organ or cell.

b. the reduction of a reflex or other activity as the result of an antagonistic stimulation.

c. a state created at synapses making them less excitable by other sources of stimulation.

6. Chem. a stoppage or decrease in the rate of action of a chemical reaction.

7. Eng. Eccles. Law. an order, esp. from a bishop, suspending a priest or an incumbent from the performance of duties.

[1350-1400; ME inhibicio(u)n < L inhibition- (s. of inhibitio). See INHIBIT, -ION]

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I

In enzymology, a phenomenon in which a compound (an inhibitor), usually similar in structure to the substance on which an enzyme acts (substrate), interacts with the enzyme so that the resulting complex cannot undergo the usual reaction or cannot form the usual product.

The inhibitor may function by combining with the enzyme at the site at which the reaction usually occurs (competitive inhibition) or at another site (noncompetitive inhibition). See also allosteric control, feedback inhibition, repression.

II

In psychology, the conscious or unconscious suppression of free or spontaneous thought or behaviour through the operation of psychological impediments, including internalized social controls.

Inhibition serves useful social functions such as protecting oneself and others from harm and enabling the delay of gratification from pleasurable activities. Both extreme lack of inhibition and excessive inhibition can be personally destructive. Inhibition also plays an important role in learning, since an organism must learn to restrain certain instinctual behaviours or previously learned patterns in order to master new patterns. In physiological psychology, inhibition refers to the suppression of neural electrical activity.

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▪ enzymatic reactions

      in enzymology, a phenomenon in which a compound, called an inhibitor, in most cases similar in structure to the substance (substrate) upon which an enzyme acts to form a product, interacts with the enzyme so that the resulting complex either cannot undergo the usual reaction or cannot form the usual product. The inhibitor may function by combining with the enzyme at the site at which the substrate usually combines (competitive inhibition) or at some other site (noncompetitive inhibition). In the latter, the inhibitor does not prevent binding of the substrate to the enzyme but sufficiently changes the shape of the site at which catalytic activity occurs so as to prevent it.

▪ psychology

      in psychology, conscious or unconscious constraint or curtailment of a process or behaviour, especially of impulses or desires. Inhibition serves necessary social functions, abating or preventing certain impulses from being acted on (e.g., the desire to hit someone in the heat of anger) and enabling the delay of gratification from pleasurable activities. Conscious inhibition is a common occurrence in daily life and is present whenever two conflicting desires are experienced (e.g., the desire to eat a rich dessert versus the desire to lose weight).

      Psychoanalytic theory views inhibition as a largely unconscious mechanism that mediates between the superego (the conscience) and the id (primitive desires). Taboos, such as those against incest or murder, are those socially imposed inhibitions which are raised to the level of unwritten laws.

      An extreme lack of inhibition may be antisocial and a symptom of certain mental disorders, particularly behaviour disorders, sociopathic personality disorders, and schizophrenic disorders. Conversely, too much inhibition can be personally destructive, resulting in the neurotic inability to feel or express certain emotions, or in sexual frigidity or impotence.

      The ingestion of alcohol and certain drugs, particularly sedative-tranquilizers (e.g., chlordiazepoxide and diazepam), hypnotics (e.g., flurazepam), and certain narcotics, may reduce inhibitions. The effects will vary from person to person.

      Inhibition also plays an important role in conditioning and learning, because an organism must learn to restrain certain instinctual behaviours or previously learned patterns in order to master new patterns.

      In physiological psychology, the term inhibition refers to the suppression of neural electrical activity.

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